The hydrogenosomes are unusual organelles present in certain anaerobic unicellular eukaryotes such as trichomonads, cilliates, amoeboflagellates and fungi. They were discovered independetly at the Rockefeller University in New York (Lindmark and Muller, J. Biol. Chem., 248:7724-7728, 1973) and at the Charles University in Prague (Cerkasovova, A., Lukasova, G., Cerkasov J., and Kulda, J., J. Protozool., 20:537, 1973) more than 30 years ago.

However, the origin of these organelles is still question of debates:

1. Are they derivatives of mitochondria?

2. Did they evolve independently from anaerobic bacteria?

3. Did they derive from peroxisomes?

4. Did hydrogenosomes and mitochondria evolve from a common proteobacterial ancestor?

Our recent investigations of components mediating FeS cluster assembly in hydrogenosomes as well as discovery of NADH dehydrogenase modul of mitochondrial complex I favor #4 hypothesis.